An error occurred when i tried to view struts example

[M . Amin]

Dear All,
 I'm a newbie to struts and i'm interested in its MVC paradigm but when i tried
to lauch struts-blank applicaton example i got the following error message :


Error: 500

Location: /struts-blank/index.jsp

Internal Servlet Error:

javax.servlet.ServletException: Missing message for key index.title
        at 
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:459)
        at 
_0002findex_0002ejspindex_jsp_0._jspService(_0002findex_0002ejspindex_jsp_0.java:227)
        at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:119)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
        at 
org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.java:177)
        at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:318)
        at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:391)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
        at org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:404)
        at org.apache.tomcat.core.Handler.service(Handler.java:286)
        at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372)
        at 
org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:797)
        at org.apache.tomcat.core.ContextManager.service(ContextManager.java:743)
        at 
org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:210)
        at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416)
        at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498)
        at java.lang.Thread.run(Thread.java:475)

Root cause: 

javax.servlet.jsp.JspException: Missing message for key index.title
        at org.apache.struts.taglib.bean.MessageTag.doStartTag(MessageTag.java:242)
        at 
_0002findex_0002ejspindex_jsp_0._jspService(_0002findex_0002ejspindex_jsp_0.java:90)
        at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:119)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
        at 
org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.java:177)
        at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:318)
        at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:391)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
        at org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:404)
        at org.apache.tomcat.core.Handler.service(Handler.java:286)
        at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372)
        at 
org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:797)
        at org.apache.tomcat.core.ContextManager.service(ContextManager.java:743)
        at 
org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:210)
        at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416)
        at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:498)
        at java.lang.Thread.run(Thread.java:475)

Any help will be appreciated.

Regards,
 M. Amin